[performance] Lazy data formatting

[markov00]

We apply data formatting on every data point before rendering, even if they are not shown on the screen.
This was a design decision to improve the subsequent rendering of the tooltip and any other dynamic value displayed when interacting on the chart.

This is fine for small charts, but it comes with a price when rendering heavy-load charts. It also depends heavily on the formatting function used.

The proposal is to remove this capability and apply formatting only at rendering time and when needed.
This could reduce the computation time and also the memory utilization